1. Field of the Invention
The present invention relates to a flow rate measuring apparatus installed in, for example, an intake pipe through being inserted into an insertion hole formed in the intake pipe, for measuring a flow rate of air passing through the intake pipe.
2. Description of the Related Art
Conventionally, there is known a flow rate measuring apparatus including a flow rate detection element for detecting a flow rate of air flowing through an intake pipe, a circuit board for driving the flow rate detection element, and a support member for supporting the circuit board and the flow rate detection element (for example, see Japanese Patent Application Laid-open No. 2009-008619 (paragraphs 0012 to 0031)).
The resin support member includes a base and a plate which is superimposed and bonded onto the base with a bonding material and on which the circuit board and the flow rate detection element are placed. The support member includes a stepped portion formed between a region facing the circuit board and a region facing a detection portion of the flow rate detection element, the region facing the detection portion being thinner than the region facing the circuit board.
In the flow rate measuring apparatus having the above-mentioned configuration, when the region facing the detection portion of the flow rate detection element, which is thinner than the region facing the circuit board, is deformed due to curing treatment for the bonding material or a temperature change under a usage environment, deformation occurs while the stepped portion serves as a starting point of the deformation. As a result, stress is applied to the flow rate detection element arranged in a vicinity of the stepped portion, which causes a problem in that flow-rate detection accuracy is reduced.